Genes are heritable units, made of a sequence of deoxyribonucleic acid (DNA) contained in every cell of your body. They act as codes to produce all the proteins and determine all your characteristics from height, weight, color of skin and eyes to how good you are at memorizing stuff. Moving further in that line, genes determine your abilities as an athlete. Without going into the complexities of a complicated scientific explanation, you can just imagine those genes that code for the proteins building your calf and thigh muscles and the proteins in your blood that help carry oxygen, so that you have lots of energy and don’t easily get tired while running fast. Precisely, all those are requirements for a good athlete.
Research has found that genetics (genetics is the study of genes) may determine 20-80% of an athlete’s performance. The twenty-first century witnessed a huge accomplishment in medical science – the completion of the Human Genome Project. It made available to us our entire genetic readout. Researchers have found that our abilities to perform strenuous physical activities is dependent on a number of our genes. We all have two copies of each gene, one inherited from our dad and the other from our mom. Let us imagine, a kid has a bad copy of the gene responsible for carrying oxygen in his blood. This will mean that he becomes a slower student in the physical education class compared to his fellow student who has both good copies of the same gene. Not only a particular gene, but also a specific variant of the gene is found more commonly in athletes, depending on what type of sports they perform – power or endurance type. Variants of a gene (also called alleles) refer to the different forms of a single gene that may be present in our body. Remember that genes are made of a sequence of DNA.
Now, this sequence readout may vary for the same gene. Depending on this difference of DNA sequence readout, a gene has one or more alleles. In 2003, a group of scientists from Australia demonstrated that ATCN-3 gene is closely related to athletic performance. ATCN-3 gene produces the protein α-actinin-3 expressed in fast-twitch muscle fibers and is responsible for generating force for high-velocity movement that is important for power sports. Two alleles of ACTN-3 have been found- R allele, producing the most active form of the protein and X allele, producing the less active form of the protein. The scientists found that male elite sprinters have a much higher frequency of RR (remember that we possess two copies of each gene) alleles of ATCN-3 gene than male elite endurance athletes and non-athletes. Elite endurance athletes predominantly possess the RX alleles. Studies by other research groups confirmed that there is extremely low to no frequency of XX alleles in most elite power athletes and this result is consistent in different racial groups accounted for in the studies.
Another potential ‘sports’ gene with distinct allelic drifts between power and endurance athletes is the ACE (Angiotensin converting enzyme) gene. ACE activates a hormone angiotensin that regulates constriction of your blood vessels, which in turn, controls the rate of blood flow through the circulatory system of your body. Thus, ACE activity regulates blood pressure and has an effect on cardiac health. ACE also helps retain salt-water in your body that allows cells to stay healthy and metabolize better to produce lots of energy. The two most common variants of ACE are I and D. The I allele produces the enzyme with lower activity and the D allele produces the enzyme with increased activity. Scientists have found that endurance athletes like rowers and triathletes have a higher frequency of the I variant while the power athletes like elite swimmers and sprinters tend to possess the D allele. Many other genes related to respiratory capacity and cardiac health are being widely studied as associated with improved athletic capabilities. One such gene NRF1 is found more active in endurance athletes. And there are many more to add to this list that help determine an athlete’s potential or limitation.
So far, we have seen that apart from behavioral and environmental factors like rigorous training and exercise that are mostly accounted for contributing to athletic excellence, genetic predisposition also steers one’s chance towards being the star athlete. Some national team coaches even think it is beneficial to have genetic testing done on the candidates during selection of national team members. It will help them choose the handful who have the right genetic variant and thereby providing them with rigorous training, they can build a ‘superpower’ team. A Colorado-based genetics company called Altas Sports Genetics, that recently came into news, claims to offer inexpensive genetic tests to determine if a kid is predisposed towards the sports niche, and if at all, then to which type – endurance or power. This suggests parents can use this test to help them decide if their kid would excel on a baseball field or has great talents as a swimmer.
It is beneficial if the athletes have a basic knowledge of genes that relate to one’s athletic abilities. A detailed knowledge of those complex pathways by which these genes work is, however, not necessary. It is sufficient to know about the genetic variants and how they effect the physiology with respect to better athletic performance. It is, of course, not expected that every athlete has the right combinations. But, if they have the basic genetic knowledge that build up their ‘athletic’ physiology, it will be useful for them to customize their diet or training accordingly to promote better health and performance. Consider the example of the kid carrying one good copy of the gene regulating oxygen-carrying capacity of the blood. To supplement his genetic build-up, a diet rich in iron would make up for his inherent less oxygen-carrying capacity. He can also join specific yoga classes to help him be trained to be able to hold more oxygen volumes in his lungs.
It can become a matter of debate if the genetic information of the elite athletes would be made public. With genetic testing made widely available, it may happen that an athlete’s genetic information is made available on trading cards just like their height and weight. As a society, we tend to be curious of private lives of great athletes like Tiger Woods or David Beckham. The bigger a celebrity he is, the less privacy an athlete has in his life. Let alone the fact that the news overflows on their performance and abilities related to the sports; their personal lives, likes and dislikes, thoughts and emotions all get documented by the media. On top of this, the exposure of their genetic information to the public will leave them with almost no privacy. Alarmingly enough, the public exposure of their genetic information may even lead to viewing of the athlete’s successes to be generated not only from how well they perform based on years of perseverance but also from just their inherent traits.
However, it is not wise to consider one’s athletic abilities to be dependent on only the variations of a single or a couple of genes. The way our physiology is maintained in response to a network of genes and genetic pathways is far more complex than we can imagine. Gene expression is an entire field of study that investigates all those factors that help the expression of a gene to produce the functional protein. There are instances where you have the correct gene variant on your DNA strand, but it does not get expressed. It can be based on several factors like the effect of neighboring stretches of highly silent DNA regions (these regions on the DNA suppress the expression of their neighborhood genes) that eclipse the gene expression, presence of other silencer proteins inhibiting gene expression or absence of the helper proteins called transcription factors to induce gene expression. Thus, it seems less likely that all of the best athletes on this planet have the exact combination and proportionate expression of all the ‘superpower’ genes. Studies of the ATCN3 in a famous Olympic long jumper show that he has no copies of the R variant, but still he is the star. There are lots of environmental factors like nutrition, coaching, careful planning and a disciplined lifestyle that play a major part. You may have the right set of genes, but if you are a chain-smoker or a couch potato, you will ruin all your ‘inherent’ athletic potentials. Genes are, of course, important determinants of your predisposition in a particular field, but you must nurture yourself to reach your potential, otherwise, everything is just a waste. Whatever the genes are, you have to strive for excellence. The knowledge of genetics would help you to know more about yourself – what your body needs more of or it already has sufficiently. This will help your training and diet planned better to suit your needs. Have a positive mental attitude and keep working out harder – there is no reason why you can’t be a great athlete!
Riddhita Chakraborty, University of Utah, Department of Biology
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